Skyscrapers and yachts are so passé. This week two technology billionaires have been tussling over who has the more impressive rocket. Elon Musk’s SpaceX, which already ferries cargo to the International Space Station, secured a NASA contract on November 20th to transport astronauts too, from 2017. But Jeff Bezos of Amazon announced on Tuesday that his company, Blue Origin, had sent an unmanned capsule to the edge of space and then landed its booster rocket back on the launch pad—a big deal, because reusable rockets could dramatically cut the cost of access to space. In a series of tweets, Mr Musk, whose Falcon booster has yet to make a successful powered landing, sniffed that Blue Origin can only do suborbital launches, whereas SpaceX sends things into orbit, which is much harder. All eyes are now on the next Falcon flight, planned for December. Will Mr Musk, in turn, one-up Mr Bezos?